Is there a procedure for radio modular approval under the Radio Equipment Regulations?

There is nothing in the RED and RER specific for radio modules, or radio’s intended for installation into other equipment. Therefore, a radio module is just like any other piece of radio equipment in the EU and UK, assuming it provides the radio function.

In the EU/UK, if the radio module manufacturer has defined their module as radio equipment within scope of the RED/RER, they must apply the CE Mark/UKAS Mark as evidence of compliance with the essential requirements of the RED/RER. Unlike North America, it is not an option in the EU/UK to supply such a module without that evidence, even in cases where the market for a product is exclusively business-to-business.